A novel two-stage approach is invoked for the laser enrichment of sulphur isotopes. It consists of sequentially photolysing SF6 at −78 °C in the same cell with different lines of the CO2 laser in different stages. The requisite chemical link between the stages is facilitated by carefully controlling the presence or absence of a scavenger during irradiation. Our results show that enrichment of S-33 is viable by such an approach.